On Tue, Aug 27, 2002 at 04:05:51PM +0200, Christian Holm Christensen wrote:
> > Mac OSX is UNIX but,
> Not really, see below.
In terms of core system services and general unix environement,
MacOSX is closest to 4.4BSD, with some BSD services replaced
by Mach services. This is pretty far from Linux in many ways,
but fairly close to {Net,Free}BSD as of 3-4 year ago.
> > alas, Steve Jobs figured case sensitivity would confuse the
> > masses...
>
> Don't you just love it when people make these unilateral decisions for you?
Negative. By default, MacOSX is installed on the classic Mac HFS filesystem,
which is not case sensitive. One can also install MacOSX on a UFS filesystem
and have filename case sensitivity (and break a few Mac applications).
> > >> I'm working on getting brat running under Mac OSX. So far I have
> > >> ROOT running fine
>
> Did you need some special tricks? If so, could you summarise them on
> some WWW-page? Thanks.
I have built the CVS version of ROOT out of the box, no tricks necessary.
I used the latest Apple developer tools.
> > >> and brat half-running; brat compiles fine, but seems to have
> > >> trouble with accessing the compiled headers.
>
> Compiled headers? We do not compile headers. CINT has this odd idea
> of `precompiled headers' - like with MSVC - which I must confese I
> don't truely understand. Could you give a bit more info? thanks.
MacOSX's hacked GCC uses "precompiled system headers". This is not part
of vanilla gcc, but they are working on it.
> > >> In any case, I would like to request that the brat developers avoid
> > >> introducing classes whose names are only distinguished by
> > >> letter case.
This is a good idea in general. Refer to the perennial case-sensitivity
flame-wars for good arguments for either way.
> > > I am sure this is right but I though this was a unix system - O well.
> So did I. Heck, there commercials say so (they brag about `/dev/null')
>
> Infact, MacOSX is not really a Unix. It's a FreeBSD layer on a Mach kernel.
In fact, MacOSX is closer to UNIX than Linux is, that is if one holds
that UNIX==BSD.
The ancestry of MacOSX is murky, but it appears to have branched off
around 4.3BSD, via early BSD "single server" Mach work at CMU, at Next
and elsewhere. It thus predates 386BSD, NetBSD and FreeBSD.
However, the busy beavers at Apple are working on replacing the current
MacOSX userspace with the latest FreeBSD userspace. MacOSX 10.2
is supposed to have some of this already, but it did not make it this
far North yet. I'll keep you posted.
> What that means is that the kernel is really a microkernel,
> while a Unix kernel is a monolithic kernel (see the
> Torvalds/Thanembaum discussion). The FreeBSD layer (a translator, and
> the only one) is just there to make a POSIX interface for the
> applications.
Generally incorrect. MacOSX is a classic implementation of
a BSD "single server" running on top of the Mach microkernel. Refer to
the early CMU Mach papers, circa 1992.
--
Konstantin Olchanski
Email: olchansk@triumf.ca
Snail mail: 4004 Wesbrook Mall, TRIUMF, Vancouver, B.C., V6T 2A3, Canada
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